1. Field of the Invention
This invention relates to a duct-adjusting screw unit, for an ink blade of an ink duct of a printing press, having a contact pressure bolt extending through a threaded bore of a housing of an ink duct and acting on the ink blade, and having a device indicating the position of the duct-adjusting screw with an actuating lever.
2. Description of Prior Art
With various printed products, the requirement for printing ink is often quite different over the entire width. It is thus desired that an ink supply from an ink duct to a ductor does not take place evenly, but rather as a function of the local need. Thus, the ink ductors of a printing presses have appropriate duct-adjusting screws, whose contact pressure bolts extend through a housing of the ink duct and press in an adjustable manner on an ink blade. With a basic design of most conventional printing presses, duct-adjusting screws are very simple screws having a screw thread, which can be manually screwed in and out for adjustment. One problem is that the adjustment of the duct-adjusting screw is time-consuming, and thus relatively great amounts of waste are generated. Accordingly, printing presses are often retrofitted by removing entire ink ducts and installing new ink ducts, which have duct-adjusting screws which can either be more accurately set or have appropriate indicator devices for immediately setting the same position of the duct-adjusting screws when a defined printing process is repeated. This is achieved most exactly with screwable displacement devices, which are coupled with a counter. Such systems are known, for example, from U.S. Pat. No. 2,607,315 or from European Patent Reference EP-A-0 425 432. Ink ducts with duct-adjusting screws displaced by pivotable levers and whose contact pressure position is thus visible from a position of the pivot lever, are somewhat less precise, but more quickly adjustable. Such systems are also known in various designs and reference is made in this context for example to PCT Reference WO-A-94/19194, U.S. Pat. No. 4,479,434, German Patent Reference DE-A-25 50 720 and German Patent Reference DE-A-33 36 919, as well as Swiss Patent Reference CH-A-647 716.
Practically all mentioned conventional solutions require appropriately adapted ink ducts, and only a few are known for retrofitting existing ink ducts, wherein the simple duct-adjusting screws are removed and replaced by appropriate, specially produced duct-adjusting screw units. One main problem is that there are no standards for ink ducts, and different ink ducts are employed with each model of a printing press and with almost all types of the same model. These systems only have in common that appropriate bores, through which the contact pressure bolt is guided, are provided in the housings of the ink ducts. Depending on the system, the bores are of different length, have various diameters and are either simple bores or threaded bores. In many cases there are changes in the diameter within the bore. Accordingly, to retrofit existing ink ducts, it would require type-specific, specially manufactured different duct-adjusting screw units, wherein changes would also have to be made in the housings of the ink ducts. The adaptation of a printing press is therefore also correspond ingly expensive. With conventional systems it is either necessary to attach a completely new ink duct with appropriate duct-adjusting screw units, or the press to be retrofitted is idle for an extended time, because the existing ink duct must be removed, bores changed, the duct-adjusting screw units inserted and the ink duct reinstalled. This requires a long retrofitting time, during which an accompanying work loss additionally increases costs.
As Applicant learned from own experience, an enormous number of different basic types are necessary for retrofitting the printing presses on the market. Accordingly, warehouse expenses are high.